Rock drill water feed system



Jan 6, HWYU M WQRMAN ET AL ROCK DRILL WATER FEED SYSTEM Filed March 21, 1968 2 6 W 8 5 7. 5 r & w

6 2 9 O 4\ 3 4 a m \6 \4 3 O .U 3 M w 2 m m m N 0 W T NMV. we H 8 mmmw WV 7 l W ATTORNEY United States Patent US. Cl. 173-78 3 Claims ABSTRACT OF THE DISCLOSURE An automatic water valve for a rock drill that opens in response to an air pressure signal and automatically varies its opening to reduce high water pressures to a substantially uniform pressure in the flushing water tube of the drill. Maintaining a uniform flushing water pressure maintains a uniform rate of flow of the flushing water to the drill bit.

Background of invention This invention relates to water flow control valves for rock drills.

Conventional rock drills having means for feeding flushing water to the rock drilling bit contain a valve which is either fully open or fully closed. The use of these drills with high water pressures results in an unduly high rate of water flow into the drilling hole which is not only wasteful but is likely to damage the rock drill. Whenthe pressure of the flushing water is too high, the water backs up into the working parts of the drill causing improper lubrication, the formation of rust and other types of corrosion, loss of drilling speed and accelerated wear.

Summary of invention The principal object of this invention is to overcome the foregoing problem and to prevent the back-up of water into the drill mechanism.

Other important objects include the following: to main- "ice FIG. 1 showing the valve in a longitudinal section and with the valve in a fully closed position; and

FIGS. 3 and 4 are views similar to FIG. 2 illustrating the valve, respectively, in a fully open position and in a partly open position.

Description of preferred embodiments The rock drill 1 shown in FIG. 1 conventionally includes a body composed of a casing 2 and a backhead 3 attached to the rear end of the casing 2. A handle 4 is integrally mounted on the backhead 3. The casing 2 contains a cylinder 5, a piston 6 sliding in the cylinder 5 and a water feed tube 7 extending forward from the backhead 3 through the cylinder 5 and the piston 6. The backhead 3 contains a rearwardly opening bore 8 adapted to receive a water valve and connected to the rear end of the water feed tube 7.

The bore 8 includes two annular undercut grooves 9 and 10 which are axially spaced and divide the bore 8 into three spaced portions including an outer threaded portion 12, an intermediate portion 13 and an inner portion 14. The outer threaded portion 12 is larger in diameter than the other two portions 13 and 14, which are smooth-walled.

, The rear end of the water feed tube 7 is enlarged as a flange 17 and this flange 17 is contained in the inner end of the bore 8 and is seated on a resilient washer 18 located at the end of the bore 8.

The rock drill backhead 3 further contains an air passage 20 running to the annular groove 9 and a water supply passage 21 running to the annular groove 10. Both of these passages 20 and 21 extend from conventional supply inlets which are not shown. In addition, the air passage 20 extends from a conventional air control valve which is not shown but which is normally connected to the throttle valve (not shown) for the rock drill 1. Normally, the

tain a substantially uniform flow and pressure of water through the water flushing tube of a drill over a wide range of high water supply pressures; to provide an automatic water pressure reducing valve which can be installed in a conventional rock drill without any modifications;

and to provide a water valve for a rock drill which is responsive to air pressure to open and is also responsive to water pressure to maintain the water pressure and flow in the flushing tube of a rock drill substantially uniform regardless of water supply pressures;

In general, the objects of this invention are obtained in a rock drill having a feed water tube, a water supply passage, a valve interconnecting the feed water tube and the water supply passage to control the flow of water into the feed water tube, a valve-operating member connected to the valve by a resilient means urging the valve and valveoperating member toward each other, and surfaces on the valve and valve operating member subject to pressure in the feed water tube to urge the valve toward a closed position away from the valve operating member to reduce water pressure entering the feed water tube and to maintain the pressure in the feed water tube at a substantially uniform pressure regardless of the pressure of the supply water.

Brief description of drawings The invention is explained in connection with the accompanying drawings wherein:

FIG. 1 is a longitudinal section of the rear portion of a rock drill illustrating the mounting location for the automatic water valve of this invention;

FIG. 2 is an enlarged fragmentary view of a portion of opening of the throttle valve to a selected position will admit air pressure to the air passage 20.

The invention in this application resides in the valve mechanism 26 which is mounted in the bore 8. The valve mechanism 26 includes a plug-shaped body 27 having a head 28, a threaded annular mid-portion 29 and an annular nose 30. The valve body 27 has a stepped diameter with the head 28 having the greatest diameter, the threaded mid-portion having a smaller diameter and the nose 30 having the smallest diameter.

The threaded mid-portion 29 of the valve body 27 threads into the threaded outer portion 12 of the bore 8 as shown in FIG. 2. The nose 30 of the valve body 27 contains a groove and O-ring 32 to engage the Walls of the intermediate portion 13 of the bore 8 in a sealing manner. A larger O-ring 33 is carried at the root of the head 28 and seats in an annular rabbet 34 circling the mouth of the bore 8.

The valve body nose 30 is hollow and surrounds a valve seat 36 attached over the end of the flange 17 on the feed water tube 7. The valve seat 36 is spaced from the valve body nose 30 to provide an annular space through which feed water can flow from the water supply passage 21 to the feed water tube 7.

The valve body 27 is hollow and contains a sliding valve 37 having a reduced diameter forward plunger 38 adapted to engage the valve seat 36 to close otf the flow of water into the tube 7. The plunger 38 slides in an annular rib 39 provided in the valve body 27. The annular rib 39 contains an O-ring seal 40. The valve seat 36 contains an upstanding sleeve-like flange 41 adapted to engage the sides of the plunger 38 to aid in progressively metering the flow of the water during the movement of the valve plunger 38. The valve 37 includes an enlarged head 42 carrying an O-ring 43 for sealing purposes and a threaded rod 44 projecting rearwardly from A valve operating member 46 slidably fits over the rod 44 and has a reduced diameter stem 47 which seats against the head 42 of the valve. The stem 47 includes respective inner and outer O-rings 49 and 50 for sealing purposes. The valve operator 46 further includes an upper piston 51 carrying an O-ring seal 52 and sliding in an enlarged cavity in the valve body 27. The piston 51 cooperates with the walls of the valve body cavity to form an actuating chamber 53 located below the piston 51. The valve body 27 contains a passage 54 running from an annular chamber 53 for conveying air from the air passage 20 to the actuating chamber 53 for lifting the valve operator piston 51.

The valve operator 46 is resiliently urged against the valve 37 by a spring 56 which fits over the threaded rod 44, and abuts a nut 57 threaded on the rear end of the threaded rd'44. Both the valve 37 and the valve operator 46 are resiliently urge forward by a spring 58 which engages the rear of the valve operator piston 51 and the inside of a cap 59 which is locked in the rear end of the cavity in the valve body head 28 by a resilient retaining ring.

The front surface of the valve head 42 is vented through a passage 60 which extends rearwardly through the valve rod 44 and a vent port 61 in the cap 59. This venting is necessary to prevent any pressure build-up on the forward surface of the valve head 42 which would interfere with the forward movement of the valve 37.

The surface located between the valve head 42 and the valve operator stem 47 forms a chamber 63 which communicates with the water feed tube 7 by a passage 64. Thus, water pressure in the water feed tube will enter the chamber 63 and act on the surfaces of the chamber 63 to urge the valve 37 away from the valve operator 46 with the spring 56 resisting the Water pressure in the chamber 63. The valve 37 and valve operator 46 will move farther apart as the water pressure rises. This movement of the valve 37 relative to the valve operator 46 results in a automatic metering of the water flow past the valve to achieve a substantially constant water pressure in the water feed tube 7 regardless of the pressure in the water supply passage 21. Maintaining a constant water pressure in the water feed tube 7 results in a constant flow of water through the feed tube 7 into the hole being drilled.

While a single embodiment of the invention is illustrated and described, it should be understood that this invention is not limited merely to the particular structure described in the specification and shown in the drawings, but may include other embodiments and modifications utilizing the concepts and teachings of the invention.

We claim:

1. A rock drill comprising:

a rock drill body including a water feed tube and a water supply passage for conveying water to said feed tube;

v i a valve interconnecting said water feed tube and said watersupply passage to control the flow of water into said feed tube; and

automatic valve operating means operatively associated with said valve for progressively varying the movement and position of said valve to reduce the pres- 7 sure of the Water entering said feed tube and to maintain the pressure in said feed tube substantially uniform irrespective of the water pressure in said water supply passage.

2. A rock drill comprising:

a rock drill body including a water feed tube and a water supply passage for conveying water to said feed tube; V I

a valve interconnecting said feed tube and said water supply passage to control the fiow of water into said feed tube; and

valve operating means operatively associated with said valve for progressively varying the opening movement and position of said valve in response to the pressure in said feed tube in order to maintain the water pressure in said feed tube substantially uniform over a wide range of pressures in said wate supply passage.

3. A rock drill comprising:

a rock drill body containing a water feed tube and a water supply passage;

valve means interconnecting said feed tube and said water supply passage and operative to control the water flowing into said feed tube from said water supply passage;

said valve means including a valve seat and a valve movable between open and closed positions;

a valve operating member located adjacent said valve;

resilient means operatively associated with said valve and said valve operating member for resiliently urging said valve and said valve operating member toward each other;

cooperating surfaces on said valve and said valve op erating member operative when subject to pressure to urge said valve and valve operating member apart; and

a conduit communicating with said water feed tube for conducting water pressure from said water feed tube to said cooperating surfaces to cause said valve to move into a position wherein the water pressure entering said feed tube is reduced to a substantially uniform'pressure regardless of the pressure in said water supply passage.

References Cited UNITED STATES PATENTS 2,725,854 12/1955 Lear l7378 X 2,882,861 4/1959 Hillman 173-78 X 2,905,442 9/1959 OFarrell 173-78 X NILE c. BYERS IR., Primary Examiner 

